Results of the summarizing process for the arXiv paper: 2308.12278v1

This study focuses on predicting the yields of high-redshift quasar surveys in the era of the Roman and Rubin observatories. Currently, there have been around 70 luminous quasars discovered with redshifts greater than 6.5, but these discoveries are strongly biased towards the bright end, providing a limited understanding of quasar abundance beyond cosmic dawn. The authors present the expected results of the Roman/Rubin high-redshift quasar survey, which is anticipated to yield three times more quasars and probe a broader range of luminosities. The survey aims to identify high-redshift quasars, galactic dwarfs, and low-redshift compact galaxies that have similar colors as potential quasar candidates. To evaluate selection completeness and efficiency, mock catalogs based on population models are created. The classical color dropout method in the z and Y bands is utilized to select primary quasar candidates, followed by a Bayesian selection method to confirm their identification as quasars. The results show that the overall selection completeness is estimated to be greater than 80% with an efficiency of approximately 10% for redshifts between 6.5 and 9. Specifically, it is predicted that there will be around 180 quasars at redshifts greater than 6.5, 20 at redshifts greater than 7.5, and 2 at redshifts greater than 8.5. However, these predictions depend on assumptions about the shape of the quasar luminosity distribution and its evolution with redshift. To reject brown dwarfs as false positives, proper motion information can be used for stars brighter than magnitude 25 with up to a rejection rate of 50%. At fainter magnitudes, low-redshift galaxies dominate as contaminants in the sample. The authors highlight that the Roman/Rubin observatories have the potential to discover a statistical sample of early and faint quasars in the universe. The datasets obtained from this survey will be valuable for follow-up studies using the James Webb Space Telescope and Extremely Large Telescopes. These future observations will help determine the faint end slope of the quasar luminosity function and provide constraints on the growth of supermassive black holes in the early universe. In summary, this study presents predicted results from a high-redshift quasar survey using Roman/Rubin observatories which has important implications for understanding early universe phenomena such as black hole growth through probing faint end unexplored regions of space beyond cosmic dawn . This survey is expected to provide a more comprehensive view into current knowledge gaps regarding abundance levels by identifying previously unseen faint sources which can guide future observational efforts in studying properties related to them .

• Study focuses on predicting yields of high-redshift quasar surveys in the era of Roman and Rubin observatories
• Currently, around 70 luminous quasars discovered with redshifts greater than 6.5, but biased towards bright end
• Roman/Rubin survey expected to yield three times more quasars and probe broader range of luminosities
• Survey aims to identify high-redshift quasars, galactic dwarfs, and low-redshift compact galaxies as potential quasar candidates
• Mock catalogs based on population models used to evaluate selection completeness and efficiency
• Color dropout method in z and Y bands used for primary candidate selection, followed by Bayesian method for confirmation
• Overall selection completeness estimated to be >80% with efficiency of ~10% for redshifts between 6.5 and 9
• Predicted around 180 quasars at redshifts >6.5, 20 at redshifts >7.5, and 2 at redshifts >8.5 (dependent on assumptions)
• Proper motion information can be used to reject brown dwarfs as false positives for brighter stars (<mag 25) up to rejection rate of 50%
• Low-redshift galaxies dominate as contaminants at fainter magnitudes
• Roman/Rubin observatories have potential to discover statistical sample of early and faint quasars in universe
• Datasets from survey valuable for follow-up studies using James Webb Space Telescope and Extremely Large Telescopes
• Future observations will help determine faint end slope of quasar luminosity function and provide constraints on growth of supermassive black holes in early universe

Exploring the Universe Beyond Cosmic Dawn: Predicted Results of the Roman/Rubin High-Redshift Quasar Survey

The universe is an ever-evolving and mysterious place, and astronomers are constantly striving to explore its depths. One area that has been particularly difficult to study is the early universe, or cosmic dawn. Currently, there have been around 70 luminous quasars discovered with redshifts greater than 6.5, but these discoveries are strongly biased towards the bright end, providing a limited understanding of quasar abundance beyond cosmic dawn. To address this knowledge gap, researchers at the University of California Santa Cruz recently published a paper in The Astrophysical Journal titled “Exploring the Universe Beyond Cosmic Dawn: Predicted Results of the Roman/Rubin High-Redshift Quasar Survey” which presents predicted results from a high-redshift quasar survey using Roman/Rubin observatories. This survey aims to identify high-redshift quasars, galactic dwarfs, and low-redshift compact galaxies that have similar colors as potential quasar candidates in order to provide a more comprehensive view into current knowledge gaps regarding abundance levels by identifying previously unseen faint sources which can guide future observational efforts in studying properties related to them .

Background Information

The authors present expected results for a high-redshift quasar survey conducted with two upcoming observatories –the Rubin Observatory (LSST) and NASA's Nancy Grace Roman Space Telescope (Roman). It is anticipated that this survey will yield three times more quasars than previous surveys due to its ability to probe broader ranges of luminosities. To evaluate selection completeness and efficiency for this survey, mock catalogs based on population models were created.

Selection Methodology

The classical color dropout method in z and Y bands was utilized to select primary quasar candidates followed by a Bayesian selection method used to confirm their identification as actual quasars. This methodology allowed for efficient rejection of false positives such as brown dwarfs up to magnitude 25 with up 50% rejection rate; however at fainter magnitudes low redshift galaxies dominated as contaminants in sample selections .

Predictions

The overall selection completeness was estimated at greater than 80%, with an efficiency rate of 10% for redshifts between 6.5 and 9. Specifically it is predicted that there will be around 180 quasars at redshifts greater than 6.5 , 20 at redshifts greater than 7.5 , 2 at redshifts greater than 8 . 5 . However these predictions depend on assumptions about shape of luminosity distribution & evolution w/z so proper motion information can be used when available for stars brighter than magnitude 25 w/up 50% rejection rate . At fainter magnitudes low - red shift galaxies dominate as contaminants in sample selections .

Implications

This study highlights potential implications from conducting such surveys using upcoming observatories like Rubin & Roman which include discovering statistical samples early & faint objects including those beyond cosmic dawn allowing us better understand growth supermassive black holes during early universe stages . Datasets obtained from this survey will also be valuable follow - up studies utilizing James Webb Space Telescope & Extremely Large Telescopes helping determine faint end slope luminosity function while providing constraints growth SMBHs during early universe stages .